Storage mesh ring assembly support



Jan. 7, 1969 E T- M KENZIE STORAGE MESH RING ASSEMBLY SUPPORT Filed 001;. 5, 1966 I Mid-#702. inn 4x0 7.7144((51/2/5, 5y

United States Patent Olfice 3,421,038 Patented Jan. 7, 1969 3,421,038 STORAGE MESH RING ASSEMBLY SUPPORT Edward T. MacKenzie, Ramona, Calif., assignor to Hughes Aircraft Company, Culver City, Calif., a corporation of Delaware Filed Oct. 3, 1966, Ser. No. 583,839 US. Cl. 313-286 Int. Cl. H01jl/96;H01j19/50 1 Claim ABSTRACT OF THE DISCLOSURE This invention is a structure for supporting the ring assembly of an electron tube and, more particularly, for supporting the target assembly in the front envelope of an electron tube.

In the construction of an electron tube, extreme precision is required in locating the target screen or mesh of the tube relative to the viewing screen. Because of the required high degree of precision, heretofore complicated and extremely time-consuming processes were employed to mount the target screen within the front envelope. However, with the demand for larger quantities of electron tubes, a necessity has arisen for the development of a faster and more reliable method of mounting these elements. For the purpose of this description, the phrase electron tube includes, but is not limited to a direct view storage tube, an electrical read-out storage tube and a color television tube.

Therefore, it is an object of the present invention to provide an improved structure for mounting the target screen of an electron tube within the front envelope.

It is a further object of the present invention to provide a greatly simplified structure for precisely mounting the storage mesh of an electron tube in the front envelope of the tube.

.The above and other objects of this invention are accomplished in one embodiment of the present invention comprising a plurality of abutment members aflixed to the inside surface of the glass front envelope of an electron tube. A plurality of boss members are affixed to the ring assembly of the tube with each one opposing one of the support members when this assembly is positioned within the front envelope. A support member is carried by each of the boss members and is engageable with the opposing abutment member to rigidly support the ring assembly against axial movement, and to precisely locate it relative to the inside surface of the front envelope.

Other objects, features and advantages of this invention will become apparent upon reading the following detailed description of one embodiment of the invention and referring to the accompanying drawings wherein like parts 'have the same reference numerals and in which:

FIGURE 1 is a side elevational view of one embodiment of the improved structure of the present invention showing the precise positioning of the ring assembly relative to the viewing screen of the tube.

FIG. 2 is an enlarged view, shown in section, of that portion of the support structure of the present invention shown enclosed by arrows 22 in FIG. 1.

Referring to FIG. 1, the principles of the present invention are illustrated in an embodiment wherein the front envelope 10 for an electron t-u'be comprises a cylindrical dish-like member of a transparent material such as glass having a relatively flat face or viewing surface 11 and a side wall 12 with an inside surface 13. A ring assembly 14 such as the target assembly for the electron tube is in juxtaposition with the inside surface 13 and comprises at least one ring 18 of an electrically conductive material such as stainless steel. The ring 18 typically supports a storage mesh or screen 19 (shown in dashed lines) and it should be understood that additional rings such as a collimator ring and/or a collector ring may be incorporated into the assembly 14 within the principles of this invention. Typically, the additional rings would be aflixed to the storage mesh ring 18 at its exposed side by insulators (not shown), and, if desired, the support structure may be associated with the additional ring rather than the storage mesh ring 18. The remainder of the glass envelope for the electron tube is not shown, but typically comprises a cylindrical portion with a necked portion at its extremity which would be fused to the front envelope 10 along the edge 15.

Typically, an inside surface 26 of the envelope 10 is called the viewing screen, and comprises a layer of a phosphor material covered with a layer of conductive material such as aluminum. The surface receives electrons passed through the storage mesh or screen 19. The production of electrons and the control of the electrons through the storage mesh are Well-known principles and do not form part of this invention. For an understanding of the operation of an electron tube reference should be made to any standard text.

A plurality of equally spaced button-like abutment members 28 each having a central chamber 29 (FIG. 2) are affixed to the inside surface 13 of the envelope 10. In the preferred embodiment, three abutment members are used and are spaced substantially apart around the inside surface 13; however, it should be understood that a greater number of equally spaced members may be used within the principles of this invention. The abutment members 28 are of a rigid material and are affixed to the envelope by fusing them with the glass of the envelope during the manufacturing process in the procedure in forming the envelope 10.

In addition to FIG. 1, shown in detail in FIG. 2, the target ring assembly 14 is supported within the glass envelope 10 by a plurality of structures each cooperating with a different one of the abutment members 28 to rigidly retain the assembly 14 against axial movement. Each of the the structures comprise a boss member 30 retained in an aperture in the ring 18 and the boss member 30 has a central bore having a tapered or countersunk portion 34 and a threaded portion 36. A support member 38 comprising a partially threaded screw engages each of the bores. The support member includes at one end a ball-like portion 40' adapted to be inserted into one of the chambers 29 in the abutment 28 and at the other end a tapered portion is adapted to engage the counter-sunk portion 34 when the screw 38 is threaded into the central bore to provide a (flush surface between the boss 30 and screw 38.

The ring assembly 14 is supported in the envelope by the ball-like portions '40 engaging the chambers 29 in the abutment members 28, while this provides axial support as clearly seen in FIG. 2, the depth of each of the chambers is greater than the portion of the screw member inserted therein to permit the ring assembly 14 to move radially. Such freedom for radial movement is necessary to accommodate expansion of the assembly 14 during the bake-out process. The bake-out process is a conventional process of heating the assembled tube to drive off gas from the surface of the various elements.

As best seen in FIG. 1, the assembly 14 is precisely positioned in the front envelope with an accurate spacing between the storage mesh 19 and the viewing screen 26 by the simple three member structure of the present invention. The precise location of these elements is necessary because of the electrical potential maintained between them. Complicated processes such as welding are eliminated since the abutment members 28 are afiixed to the envelope as part of the manufacturing process of envelope 10 and the 13085 member 30 carrying the screw member 38 are pressed into apertures drilled in the ring 18. Many ways may be used to retain the boss 30 in the aperture; in this embodiment, it was found desirable to utilize a slot having substantially the same diameter as the aperture which is slightly less than that of the boss 30. This permits the boss to be pressed into the aperture until the slot engages the aperture periphery.

While the basic principle of this invention has been herein illustrated and has been described in one embodiment, it will be appreciated by those skilled in the art that variations in the disclosed arrangement both as to its details and as to the organization of such details may be made without departing from the spirit and scope thereof. Accordingly, it is intended that the foregoing disclosure and the showings made in the drawings will be considered only as illustrative of the principles of the invention and not construed in a limiting sense.

What is claimed is:

1. An arrangement for supporting and precise positioning a storage mesh ring assembly in the front envelope of an electron tube adjacent the viewing screen comprising:

a plurality of abutment members each having a cavity therein and so affixed to the inside peripheral surface of the envelope adjacent so as to leave said surface imperforate,

a ring member having a plurality of bosses on the periphery thereof,

each of said bosses being aligned with one of said abutment members,

each of said bosses having a support member demountably associated therewith and extending radially outwardly therefrom for deposit in the cavity of an aligned abutment member to provide support for the ring assembly against axial movement in the tube,

the support members being threadably connected to the respective bosses and removable therefrom by withdrawal radially internally of the ring said support members being only partially deposited in the cavities to accommodate radial expansion of the ring assembly during heating thereof.

References Cited UNITED STATES PATENTS 2,846,608 8/1958 Shrader 313 2,100,703 11/1937 Schlesinger 313283 X 2,488,132 11/1949 Leighton 313288 X 2,821,644 1/1958 Henry et al. 313283 X 2,922,063 1/1960 Haas 31385 3,004,182 10/1961 Pfaender 31385 ROBERT SEGAL, Primary Examiner.

US. Cl. X.R. 313-284 

